Polymers damage during analysis

There the SSIMS (Fig. 93 A) and the FABMS (Fig. 93 B) secondary positive ion spectra are compared for PTFE the surface of the PTFE has to be coated with a gold film for SSIMS measurement but not for FABMS. More fragment ions occur in the SSIMS spectrum than in FABMS, and in the FABMS spectrum the size of the peak at m/e=12 (C ) relative to the principal peak at m/e = 69 (CI ) is much smaller than in SSIMS. indicating much less damage of the polymer surface during FABMS analysis. 

As already indicated in Scheme 2.12, XRF is profitably used for general screening of polymer formulations on inorganic components, before and after extraction. In the case of several PVC blends, such screening has indicated the presence of Cl, Ca, Ti, Cr, Fe, Zn, Mo, Cd, Sn, Sb and Pb [255]. It is well known that X-ray radiation may cause radiation damage, such as coloration of PVC samples during XRF analysis. 

Relevant and complementary information about the damage process of polymers can be obtained among others by the analysis of the force-displacement curves, by the observation of the fracture surfaces (cf. Sects. 3.2.5 and 5.4) and, as will be shown in Sect. 6.2.2, by the determination of the amount of voids in a sample during and/or after deformation. However, a complete elucidation of the deformation mechanisms is only possible by their direct observation at the sub-micron level. Transmission electron microscopy is often used for this purpose. For convenience, the tests (which require experience and touch) are generally carried out at room temperature and at a low strain rate. 

Analysis of volatiles is frequently utilised in food industry to quality control food products and to determine shelf-life for various products. Some recent examples are the use of sensor arrays to differentiate milk products according to their aging times (12) and the use of solid phase microextraction-mass spectrometry-multivariate data system to predict the shelf-life of pasteurised milk (13). Volatiles emitted by plants have also been correlated to abiotic or biotic stress and the degree of damage caused by the stress (14). Similar principles should be applicable to polymeric materials i.e. the formation of certain volatiles or indicator products during degradation of the polymer is related to the changes in the polymer matrix (Fig. 1). 

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